Search Publications
Acceleration of O+ from the cusp to the plasma sheet
Dandouras, I.; Klecker, B.; Kistler, L. M. +2 more
Heavy ions from the ionosphere that are accelerated in the cusp/cleft have been identified as a direct source for the hot plasma in the plasma sheet. However, the details of the acceleration and transport that transforms the originally cold ions into the hot plasma sheet population are not fully understood. The polar orbit of the Cluster satellite…
Nebular and Stellar Dust Extinction Across the Disk of Emission-line Galaxies on Kiloparsec Scales
Sobral, David; Mobasher, Bahram; Hemmati, Shoubaneh +3 more
We investigate the resolved kiloparsec-scale stellar and nebular dust distribution in eight star-forming galaxies at z ∼ 0.4 in the Great Observatories Origins Deep Survey fields. This is to get a better understanding of the effect of dust attenuation on measurements of physical properties and its variation with redshift. Constructing the observed…
Post-starburst quasars: bridging the gap between post-starburst galaxies and quasars
Brotherton, Michael S.; Cales, Sabrina L.
In order to better understand the nature of post-starburst quasars (PSQs) in the context of galaxy evolution, we compare their properties to those of post-starburst galaxies and quasars from appropriately selected samples possessing similar redshift (z ∼ 0.3), luminosity (Mr ∼ -23), and data quality. We consider morphologies, spectral f…
Oxygen Abundance Measurements of SHIELD Galaxies
Cannon, John M.; Salzer, John J.; Marshall, Melissa V. +1 more
We have derived oxygen abundances for eight galaxies from the Survey for H I in Extremely Low-mass Dwarfs (SHIELD). The SHIELD survey is an ongoing study of very-low-mass galaxies, with MH \scriptsize{I} between 106.5 and 107.5 M ⊙, that were detected by the Arecibo Legacy Fast ALFA survey. Hα images fro…
Chromospheric Nanoflares as a Source of Coronal Plasma. II. Repeating Nanoflares
Klimchuk, J. A.; Bradshaw, S. J.
The million degree plasma of the solar corona must be supplied by the underlying layers of the atmosphere. The mechanism and location of energy release, and the precise source of coronal plasma, remain unresolved. In earlier work, we pursued the idea that warm plasma is supplied to the corona via direct heating of the chromosphere by nanoflares, c…
Gaussian approximation of peak values in the integrated Sachs-Wolfe effect
Aiola, Simone; Kosowsky, Arthur; Wang, Bingjie
The accelerating expansion of the universe at recent epochs is encoded in the cosmic microwave background: a few percent of the total temperature fluctuations are generated by evolving gravitational potentials which trace the large-scale structures in the universe. This signature of dark energy, the integrated Sachs-Wolfe effect, has been detected…
Characterizing the Atmospheres of the HR8799 Planets with HST/WFC3
Macintosh, Bruce; Pueyo, Laurent; Barman, Travis +7 more
We present results from a Hubble Space Telescope (HST) program characterizing the atmospheres of the outer two planets in the HR8799 system. The images were taken over 15 orbits in three near-infrared (near-IR) medium-band filters—F098M, F127M, and F139M—using the Wide Field Camera 3. One of the three filters is sensitive to a water absorption ban…
The Good, the Bad, and the Ugly: Statistical quality assessment of SZ detections
Aghanim, N.; Arnaud, M.; Douspis, M. +6 more
We examine three approaches to the problem of source classification in catalogues. Our goal is to determine the confidence with which the elements in these catalogues can be distinguished in populations on the basis of their spectral energy distribution (SED). Our analysis is based on the projection of the measurements onto a comprehensive SED mod…
HST Images Reveal Dramatic Changes in the Core of IRC+10216
Lee, Ho-Gyu; Chu, You-Hua; Kim, Hyosun +1 more
IRC+10216 is the nearest carbon star with a very high mass-loss rate. The existence of a binary companion has been hinted at by indirect observational evidence, such as the bipolar morphology of its nebula and a spiral-like pattern in its circumstellar material; however, to date, no companion has been identified. We have examined archival Hubble S…
On Multiple Reconnection X-lines and Tripolar Perturbations of Strong Guide Magnetic Fields
Lavraud, B.; Khotyaintsev, Yu. V.; Carr, C. M. +7 more
We report new multi-spacecraft Cluster observations of tripolar guide magnetic field perturbations at a solar wind reconnection exhaust in the presence of a guide field BM which is almost four times as strong as the reversing field BL. The novel tripolar field consists of two narrow regions of depressed BM, with an…